Even though I have been taking care of myself for 2 years now with alanon and SR, I still have times where I too feel very sad. It's like I am looking back at a life that should have been and never was.
A good cry can make you feel better too.
But, then when I am told to make a gratitude list, I CAN find things that I am very thankful for.
Think on the good things and don't dwell on the bad.
I hope you feel better soon.